Fuel System Filler Cap

Stiff filler cap

(penned by Covkid):

This is basically a cleaning/disassembly. After a time, filler caps can be stiff to turn.

If you remove the filler cap and flip it over, you'll see a small pin through the red plastic housing.

Push this through and the whole assembly comes apart.

The last part is a steel washer which invariably gets corroded, hampering the movement of the filler cap when you turn it.

Remove all the rust and coat lightly with grease (ideally silicone grease if you have it) then reassemble